Allergic rhinitis is the outcome of an IgE-mediated allergic response in the nose. Previous studies of IgE produced by B-cells in the nasal mucosa of allergic rhinitis patients have shown an increased usage of the V H5 gene family, compared to the normal blood V H gene repertoire, which has been attributed to superantigen activity. Work reported in this thesis has been undertaken to investigate further how the antibody repertoire is shaped in allergic rhinitis. IgA-expressing B-cells in the nasal mucosa, from allergic and non-allergic donors, were also shown to have an increased usage of VH5 genes compared to the normal blood repertoire, suggesting the nasal environment favours VH5 expansion prior to allergy development. Somatic hypermutation patterns in VH5-Ca sequences were indicative of superantigen selection. FACS analysis of nasal turbinate cells with antibodies to S. aureus enterotoxins (SE) demonstrated TSST -1 + cells in allergic nasal tissue only. Incubation of nasal turbinate tissue with SEs appeared not to influence the VH-Cϵ repertoire in 24 hours, but SED + IL-4 may have inhibited VH-Cϵ transcription in allergic patients. Evidence of local antigen stimulation prior to SE incubation was evident in one of the patients; a large VH5 clonal family exhibiting extensive somatic hypermutation was present throughout the nasal turbinate. FACS sorting of Phl pl-binding plasma cells and single cell RT-PCR enabled cloning of a scFv fragment representing the V regions of a physiological, allergen-specific antibody expressed in allergic nasal mucosa. The scFv cloning protocol has also been applied to VH5 genes of interest, thus facilitating the study of their protein structure and function. This research increases the evidence for local, VH5-selecting, superantigen activity in the nasal mucosa and has developed a platform for further investigation of nasal antibody- superantigen / allergen interactions in allergic rhinitis.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:582540 |
| Date | January 2007 |
| Creators | Harries, Helen Elizabeth |
| Publisher | King's College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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